Electric liquid flow switch



May 5, 1931. w. WALKER l fi fi ELECTRIC LIQUID FLOW SWITCH Filed Oct.18, 11929 INVENTOR HIS ATI' Patented May 5, 1931 UNITED. STATES PATENT;oFFfce WARREN R. WALKER, OF SHORT HILLS, NEW JERSEY, .ASIG-NOR TOGENERAL ELECTRQEC VAPOR LAMP COMPANY, OF HOIBOKEN, NEW JERSEY,.- ACORPORATION OF NEW JERSEY,

' momma LIQUID FLow swrrcn Application nice October 18, 929. Serial a...400,688. C

The presentinvention relates to electric switches of the liquid flowtype, and particularly to mercury switchesof small size.

The particular object of the invention is to provide a switch of thistype which will be reliable under commercial operating conditions; Otherobjects and advanta es will be obvious from the following speci cation.

The invention comprises a new and novel combination-of materials andparts to form a product having the general characteristics and theseveral original features ofutility hereinafterset forth and claimed. I

Mercury switches as commonly constructed rely upon the movement of amercury body in an envelope to make and break an electrical circuit. Inmost cases it is desirable to have the mercury respond to slightmovements ofrthe envelope. Under certain conditions, as whenthe'size'ofthe envelope is decreased, the mercury movement'becomes increasinglysluggish, so that special means have to-be availed of to maintain thedesired freedom of mercury movement. For example, the use 'of a fluidsuch as guaiacol, alcohol, benzol, or the like in the container withthemercury seems to decrease the adhesion'of the mercury to the walls ofthe container, permitting free movement of the mercury globule eventhrough very small passages. While the addition of this fluid eliminatesthe sluggishness italso introduces a new problem, in that it has beenfound to have a very undesirable eflect on the mercury, since thelatter, when agitated in its presence, has a marked tendency to break upinto small globules which do not readily coalesce, and as a result theoperation of such a switch is very; uncertain;

Applicant has found that this diificulty may be readily overcome bydissolving in the mercury a trace, say of the order of one part in athousand by weight, of nickel, platinum, or palladium. Iron, cobalt,osmium and other members of the eighth group 'of elements, copper, lead,tin andother similar metals, have also been found to be suitable forthis purpose in somewhat varying degree. Mercury modified in this mannerhas een found to give highly satisfactory results when enclosed in theusual manner in glass, quartz, or other vitreous envelopes'lnto whlchare sealed in-leads of mckel, 1ron, tungsten,

platinum, dumet, or other suitable material,

and in the presence ofalcohol, guaiacol or. other similar liquid. Whensomodified by the nickel or other metal the mercury loses the tendencyto break up into small globules which it would otherwise have in thepresence of the other fluid, any globules thereof which are formedreadily coalescing.

For the purpose of illustration two types of mercury switches embodyingm invention are shown in the accompanying rawings, in which I Fig. 1 isan elevational view of a' mercury switch in an open circuit position,

Fig. 2 is an elevational view of the switch I of Fig. 1 in a circuitclosing position,

Fig. 3 is an elevational View of the same switch with terminal capsattached thereto to adapt it for molinting in spring clips,

Fig. 4 is a plan view of a somewhat similar switch having both inleadssealedlnto one end thereof, and v switchi In these drawings, withparticular reference to Figs. 1 to 3 a tubular envelope 1 of glass orother suitable vitreous material, of say 4 inch diameter, has sealedinto one end '75 Fig. 5 is an elevational view of the same thereof aninlead 2, while into the opposite v end thereis sealed an inlead 3, saidinleads being of dumet, iron, tungsten, nickel, platinum or othersuitable metal, dumet being preferred, however, in those cases where theenvelope 1 is constructed of lead glass because of its relatively lowcost. Said inleads 1 2 and 3 extend toward each other and have a shortgap between the-ends thereof near one end of the envelope 1. Within saidenvelope 1 is a quantity of mercury 4 which is sufficient t o'close thecircuit between said inleads 2 and i 3 when said envelope is in theposition shown in Fig. 2. Since the small diameter of the envelope 1tends to prevent the free movement of the mercury 4 therein a few drops5 of alcohol, guaiacol, benzol, or other similar fluid which will reducethe adhesion of said mercury to the wall of said envelope are alsoenclosed therein. .Where Y may be produced with stance.

stance which stends to promote the switch is to be subjected to lowambient temperatures :alcohol is preferred for-this purposebecause ofits low viscosity at such tempei 'atures. Dissolved inthe mercury 4 is atrace, of say one part in a'thousand, of a metal such as mckel.Palladium, platinum, iron, cobalt, or other metal of the eighth group inthe Periodic table, copper, lead, tin or other similar metal may be usedinstead of nickel, where desired. This dissolvedj'netal has the effectof promoting coalescence of any mercury globules formed during operationof the switch, en-.

tirely overcoming the tendency toward maintenance thereof resulting fromthe use of the alcohol or similar fluid in contact'with the mercury.

Withsome of the above metals this efli'ect a concentration of only onepart in a million. As shownin Fig. 3 the completed switch placed oneither end thereof to which the inleads2 and 3 are connected, so thatthe switch may be mounted in spring clips such as have been commonlyused for electrical fuses.

With reference to Figs. 4: and 5 the inleads 12 and 13 are-fused into acommon seal at one end of the tubular envelope 11, thus adapting theswitch to a difierent type of. mounting. In all other respects theswitch of Figs. 4 and 5 is identical with that of Figs. 1 and 2.

It has been found that switches so constructed are extremely reliable inoperation, and at the internal resistance thereof is constant throughouttheir useful life. Such switches are especially useful for interruptinelectrical circuits of low voltage.

hile I have described my invention in connection with switches usingalcohol, benzol,guaiacol or like substance, it will be readilyunderstood that it is equally useful when any other substance is presentin such devices which tends to maintain the mercury in a globularcondition.

I claim:

1. In a mercury'switch, mercury, a substance which tends to promote themaintenance of globules of said mercury, an d a substance which promotescoalescence of said globules dissolved in said mercury and counteractingthe effect of said first named sub- 2. In, a mercury nance of globulesof saidmercury, and a metal dissolved in said mercury which promotescoalescence of said globules.

3. In a mercury switch, mercury, a sub stance which tends to promote themaintenance of lobules of said mercury, and a metal of the eighth groupdissolved in said mercury.

4. In a mercuryv switch, mercury, a subthe maintestance which tends topromote and nickel nance of globules of said mercury,

has metal caps 6 switch, mercury, a subthe malntedissolved-in saidmercury in suflicient quantity to cause said globules to readilycoalesce.

5. In a mercury switch, mercury, a substance which tends to promote themaintenance of globules of said mercuryfand 0.1% of nickel dissolved insaid mercury.

6. In a mercury switch, mercury, a substance such as alcohol in contacttherewith, and a substance dissolved in said mercury which promotescoalescence of globules of said mercury.

7. In a mercury switch; mercury, a substance such asalcohol in contacttherewith, and a metal dissolved in said mercury which promotescoalescence of globules of said'mercury.

8. In-a mercury switch, stance such as alcohol in contact therewith, anda metal of the eighth group dissolved in said mercury. 4

9. In a mercury switch, mercur a substance such as alcohol in contact terewith, and nickel. dissolved in said mercury in sufiicient, quantityto cause globules of cury to readily coalesce. v m 10. In a mercuryswitch of the seal vitreous envelope type, mercury, a substance such asalcohol in contact therewith, and 0.1% of nickel dissolved in saidmercury.

10. In a mercury switch of the sealed vitreous envelope type, mercury,asubstance such as alcohol in contact therewith, and 0.1% of envelopehaving a smaller cross-section than that permitting free movement ofsaid mercury, a fluid in said envelope to efiect free movement of saidmercury, and means comprising a metal dissolved in said mercury topromote coalescence of globules thereof.

12. In a mercury switc in combination, a

sealed-envelope havlng inleads sealed therein,

velope, and a metal of the eighth group dis'-.

solved in said mercury.

13. In a mercury switch, in combination, a sealed envelope havinginleads sealed therein, a mercury globule in said envelope, saidenvelope having a smaller cross-section than that permitting freemovement of said mercury, a small quantity of alcohol in said envelope,and nickel dissolved in said mercury.

igned at Hoboken in the county of Hudson and State of New Jersey this17th day of October A. D. 1929.

WARREN R. WALKER.

mercury, a subsaid mer.

CERTIFICATE OF CORRECTION, v

BatentNo. 1,803,986. May 5, 1931.

WARREN R. WALKER It' is hereby certiiied that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Page 2. line 9l, iirst claim 10, for "seal" read sealed; andlines 95. 96 and 97, strike out '10. In

a mercury switchof the sealed vitreous envelope type, mercury, asubstance such as alcohol in contact therewith, and 0.1% of" and insertinstead 11. In a mercury switch, in combination, a sealed envelopehaving inleads sealed therein, a mercury globule in said envelope said;and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent'Oifice.

Signed andsealed this 25th day of September, A. D. 1934.

Leslie Frazer (Seal) Acting Commissioner of Patents.

